1. Field of the Invention
The present invention relates to a contact probe used for measuring and evaluating the high-speed high-frequency characteristics of a semiconductor integrated circuit, a package for a semiconductor integrated circuit, a printed circuit board, and the like, and a measuring pad used for the contact probe, and a method for manufacturing the contact probe.
2. Description of the Related Art
In recent years, semiconductor integrated circuit (LSI) chips in electronic devices have been remarkably improved in the performance. With this, a clock frequency ranging from 3 GHz to 5 GHz is becoming a standard for a CPU. Further, a transmission speed in the packaging system of an electronic device reaches 500 Mbps to 1 Gbps although the growth of improvement in performance is slowing.
Further, to increase the speed and to decrease the size of an electronic device, a high-density packaging technology has received attention and the research and development of the high-density packaging technology have been actively conducted. For example, in “Fabrication of High-Density Wiring Interposer for 10 GHz 3D Packaging Using a Photosensitive Multiblock Copolymerized Polyimide” (Katsuya Kikuchi, Eun-Sil Jung, Shigemasa Segawa, Yoshihiko Nemoto, Hiroshi Nakagawa, Kazuhiko Tokoro, and Masahiro Aoyagi; Extended Abstracts of 2003 International Conference on Solid State Devices and Materials, pp. 382–383, 2003) is disclosed a report on an integrated circuit interposer that can be connected to fine bumps of a minimum pitch of 20 μm so as to laminate and package a three-dimensional semiconductor integrated circuit chip. Here, the interposer means a kind of LSI package used for mounting an LSI chip on a circuit board.
Under the above-described circumstances, a high-frequency contact probe developed for ultra-high speed signal measurement and evaluation in a microwave region has been conventionally used for high-speed high-frequency characteristics in LSIs, chip mounting packages, circuit boards, and the like.
However, an inter-electrode pitch (a pitch between a signal electrode and a ground electrode) at the tip of the probe that is conventionally widely used is approximately 100 μm even if it is the finest.
Further, the finest inter-electrode pitch of a commonly available probe (made by GGB Co., (U.S.A.) or Cascade Microtech Corp. (U.S.A.) is 50 μm.
Because even a minimum inter-electrode pitch of a conventional high-frequency contact probe is 50 μm, the characteristics of the interposer for the integrated circuit having a fine pitch of 20 μm cannot be directly evaluated. Hence, it has been desired that a contact probe having a smaller inter-electrode pitch will be developed.